Revision of the [Fe/H] – φ31–Prelationship for RRc variables

Abstract

AbstractThe relationship derived by Morganet al. (2007) for type-c RR Lyrae variables (RRc) between values of [Fe/H] – φ31–Phas been revised and expanded. New relationships are based upon Fourier coefficients of 163 RRc variables in 19 Galactic globular clusters using the metallicity scales of Harris (2010), Zinn & West (1984) and Carrettaet al. (2009). This larger database includes more low-metallicity clusters ([Fe/H] < −2.0), and the best fitting relations are found to depend upon values of logPrather thanP. The new relations are applied to various populations of RRc including Milky Way field variables, LMC globular clusters variables, ω Cen RRc, and RRc in various OGLE III databases.